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UNITED STATES PATENT OFFICE.

JOHN IRWIN, OF PHILADELPHIA, PENNSYLVANIA.

STANDARD FOR SEATS.

Specification of Letters Patent No. 18,748, dated December 1, 1857.

To all whom it may concern:

Be it known that I, JOHN IRWIN, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have in vented a new and Improved Spring and Screw Standard for Seats; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon.

Heretofore piano stools have sometimes been made adjustable to diiferent heights by means of a screw in the standard; this and other devices have also been employed for the same purpose in Dental chairs. But in these cases no elasticity has been allowed in the standard. Coiled springs also have been used but without any means of adjustability.

My invention consists in an improvement in adjustable and elastic standards for seats.

In the accompanying drawings A, represents part of the seat itself, which, with the pedestal, may be of any usual form. The seat is supported by the rod B, upon which is cut a male screw which works up and down in the female screw E, the latter being embraced by a coiled spring D. The upper end of this spring bears against a shoulder H, while the lower end of said spring rests upon the lower collar G, in the socket 0. Thus it will be seen that the standard B and screws E, are supported by the spring D while they are free to play up and down in socket C, being held steady by the two collars Gr. By means of the screws the seat may be adjusted to any desired height while the spring always gives an elastic support to the seat itself. This arrangement affords not only an unusually convenient standard for a seat but also one that is very durable, the spring and other parts not being liable to derangement, as is the case with other chairs having spiral springs. Moreover, my standard may be made at almost any price according to the workmanship, and when made very cheaply it will still be a good and serviceable article.

Having thus fully described my inven tion, what I claim and desire to secure by Letters Patent of the United States is The combination of the screw and spring, forming an improvement in adjustable and elastic standards for seats, as set forth.

JOHN IRWIN.

Witnesses:

CHARLES D. FREEMAN, MILTON B. MEDARY. 

